1. Field of the Description
The present description relates, in general, to creating realistic skin or skin systems for robots or for use with robotics or other applications in which skin or similar coverings are applied (e.g., robotics used to simulate movement of a human's or a character's face, hands, or the like). More particularly, the description is directed to an efficient (e.g., less time consuming and costly) and readily scalable method of fabricating skin systems (and skins formed using such methods) for applying over robotics, and the methods are suited for producing skins or skin systems with detailed and, often, fine exterior surface topologies and/or features.
2. Relevant Background
Durable materials that are often also flexible and elastic such as plastics and rubbers are used in many applications to create coverings or skins that are applied over an internal physical support structure or skeleton. For example, skins or skin systems are used to create realistic models of humans, animals, and characters, and when combined with robotics, such models may accurately simulate live beings.
Robotics involves the design and use of robots such as to provide programmable actuators or drivers to perform tasks without human intervention, and there have been significant demands for robotic devices (or robots as these terms may be used interchangeably) that simulate humans, animals, and other living beings or characters. These robotic characters are relied upon heavily in the entertainment industry such as to provide special effects for movies and television and to provide robots for use in shows and displays in amusement or theme parks. For example, robotics may be used to provide a character in a theme park ride or show that repeats a particular set of movements or actions (e.g., programmed tasks) based on the presence of guests or a ride vehicle or another triggering event.
It is likely that the interest in robotics will continue to expand in the coming years, and a growing area of interest is how to provide robots that appear more realistic. Many robotics companies have focused on creating robots with software, processing hardware, and mechanical actuators or drivers that allow the robots to behave more like the natural creature that is being simulated. Much work has been done to create robots that can move and even behave similar to humans such as by manipulating objects with mechanical assemblies that behave like hands configured to be human-like. Significant effort has also been directed to providing robots with realistic facial animation such as having a robot open and close its mouth to provide lip synchronization with output audio (e.g., with speech) and by providing particular facial movements including eye movement such as frowning, smiling, and the like. While many advances have been made in realistically simulating the physical movement and facial movement of a character, problems with maintaining a realistic or desired movement or facial animation still occur when the robotics (e.g., internal components of a robot including mechanical/structural portions as well as software, hardware, power systems, and the like) are covered with a skin or skin system. For example, a robot used to simulate a particular creature would be covered with skin or a covering assembly to imitate the natural or desired covering for the creature such as skin and fur/hair for many creatures, clothes for some creatures such as humans or characters (e.g., characters from animated films or television or puppets), or more fanciful covering system such as a metallic suit or any other desired covering.
In simulating humans or human-like characters, the robotics are typically covered in a skin that is fabricated of flexible material to move naturally with the underlying robotics. The skin may be formed of a rubber material or a silicone that is attached or anchored to the mechanical actuators or drivers of the robotic system, and the skin is configured to have an outward appearance similar to the character or creature being simulated by the robot. For example, the facial skins can be formed so as to have an uncanny resemblance to the character (or person) they are imitating, but often this resemblance ends when the attached robotics begin animating the face. The connection or anchoring points become apparent as the skin is pulled or pushed from behind. Additionally, the movement may be undesirably localized with movement only at the point of attachment, whereas a human face generally stretches and contracts more as a unit (or the movement is more widespread across the face), e.g., a human's skin around their nose and eyes may move when skin around the mouth moves while a typical robotic skin may only move near the connection point with the manipulating robotics.
Currently, a skin system for a robot is made using a manual process relying on skill and experience of the craftsperson creating the skin and requiring many man-hours to prototype and later fabricate based on the prototype. In the existing process, a sculpture is created, such as from clay or other moldable/shapeable materials, to represent the exterior skin shape (e.g., a person's face, a character from a movie, and so on). The sculpture is then molded, and sheet wax or a layer of clay is laid by hand into this exterior mold to define a desired thickness for the exterior skin layer. An interior core is then fabricated by hand such as by using fiberglass and resin. An exterior skin can finally be formed by pouring a rubber or other flexible material into the gap between the exterior mold and the core mold. After it is set, the skin is removed from the molds and placed on the supporting or hard shell(s) and attached to portions of the robotics.
To enhance the appearance and realism of the skin, it may be desirable for the skin's exterior surface to have fine detail in its topography and features. For example, a skin or skin system may be fabricated to cover a robotic hand or to provide a human-like or other face for a head of a robot. In such cases, it is desirable that the exterior surface of the skin have an expected appearance such as by including lines or wrinkles similar to those found in the human or other animal or character being simulated by the robotic assembly. In a particular case, a skin system for covering a robotic hand that is intended to have a human appearance would be designed to have wrinkles and lines (e.g., wrinkles/lines about the knuckles, bumps where veins/arteries may run below the surface, fingerprints, lifelines, blemishes, and the like) and may also have features such as fingernails.
With present manufacturing processes, the exterior mold assembly is carefully machined or fabricated such that its inner surfaces (surfaces facing the inner core) provide the desired fine detail or topography/features of the skin's exterior surface. A problem arises, though, because there are two or more sections or halves of such a mold assembly that are assembled over (or that enclose) the inner core. As a consequence, when a soft skin is manufactured for a robot or other application, the soft skin has relatively large seam or part lines/ridges where the exterior mold sections mate.
These seams or part lines/ridges have to be removed by hand or the visual realism of the skin will be ruined, e.g., an observer of the robot covered by such a skin will readily spot the seam/ridge and know the robot is artificial (not the human or character being simulated) or at least perceive the robot as less realistic. This post-processing work can be very time consuming (and, as a result, expensive) as it can be difficult to clean and trim the molded skin without damaging its exterior topography and features. This clean up or finishing work can also be heavily reliant upon the artisan performing the work such that results will vary and often may not be wholly satisfactory. Hence, there remains a need for an improved method of fabricating skins or skin systems that requires less or no post-processing work while retaining high quality detail in the exterior topography and/or features of the skins or skin systems.